High density interconnect system for IC packages and interconnect assemblies

ABSTRACT

An improved interconnection system is described, such as for electrical contactors and connectors, electronic device or module package assemblies, socket assemblies, and/or probe card assembly systems. An exemplary connector comprises a first connector structure comprising a contactor substrate having a contact surface and a bonding surface, and one or more electrically conductive micro-fabricated spring contacts extending from the probe surface, a second connector structure comprising at least one substrate and having a set of at least one electrically conductive contact pad located on a connector surface and corresponding to the set of spring contacts, and means for movably positioning and aligning the first connector structure and the second connector structure between at least a first position and a second position, such that in at least one position, at least one electrically conductive micro-fabricated spring contact is electrically connected to at least one electrically conductive contact pad.

CROSS REFERENCE TO RELATED APPLICATIONS

This Application claims priority to U.S. Provisional Application No.60/651,294, entitled Nano-Contactor Embodiments for IC Packages andInterconnect Components, filed 8 Feb. 2005, and to U.S. ProvisionalApplication No. 60/718,137, entitled Compliant Nanocontactors forApplication in Portable and High Density Electronic Systems, filed 16Sep. 2005, each of which are incorporated herein in its entirety by thisreference thereto.

This Application is also a Continuation In Part of U.S. patentapplication Ser. No. 11/133,021, entitled High Density InterconnectSystem Having Rapid Fabrication Cycle, US Filing Date 18 May 2005, nowU.S. Pat. No. 7,382,142 which is a Continuation In Part of U.S. patentapplication Ser. No. 10/870,095, entitled Enhanced Compliant Probe CardSystems Having Improved Planarity, US Filing Date 16 Jun. 2004, now U.S.Pat. No. 7,349,223, which is a Continuation In Part of U.S. patentapplication Ser. No. 10/178,103, entitled Construction Structures andManufacturing Processes for Probe Card Assemblies and Packages HavingWafer Level Springs, US Filing Date 24 Jun. 2002, now U.S. Pat. No.6,917,525, which is a Continuation In Part of U.S. patent applicationSer. No. 09/980,040, entitled Construction Structures and ManufacturingProcesses for Integrated Circuit Wafer Probe Card Assemblies, US FilingDate 27 Nov. 2001, now U.S. Pat. No. 6,799,976, which is a nationalstage of PCT Patent Application Serial No. PCT/US00/21012, filed Jul.27, 2000, each of which are incorporated herein in its entirety by thisreference thereto.

This Application also claims priority to PCT Patent Application SerialNo. PCT/US05/17881, entitled High Density Interconnect System HavingRapid Fabrication Cycle, filed 20 May 2005, which claims priority fromU.S. patent application Ser. No. 11/133,021, entitled High DensityInterconnect System Having Rapid Fabrication Cycle, claims priority to:

-   -   U.S. Provisional Application No. 60/573,541, entitled        Quick-Change Probe Chip, filed 20 May 2004;    -   U.S. Provisional Application No. 60/592,908, entitled Probe Card        Assembly with Rapid Fabrication Cycle, filed 29 Jul. 2004;    -   U.S. Provisional Application No. 60/651,294, entitled        Nano-Contactor Embodiments for IC Packages and Interconnect        Components, filed 8 Feb. 2005;    -   and is a Continuation In Part of U.S. patent application Ser.        No. 10/870,095, entitled Enhanced Compliant Probe Card Systems        Having Improved Planarity, US Filing Date 16 Jun. 2004;        each of which are incorporated herein in its entirety by this        reference thereto.

FIELD OF THE INVENTION

The present invention relates generally to the field of high densityinterconnect assembly systems, and more specifically to the fields ofsemiconductor device testing and packaging. More particularly, thepresent invention relates to high density interconnect assembly and testsystems incorporating micro-fabricated spring contacts and improvementsthereto, which improve performance, reliability, ease of use and/orlower the cost of ownership.

BACKGROUND OF THE INVENTION

Advances in semiconductor integrated circuit (IC) design, processing,and packaging technologies have resulted in increases in the number anddensity of input/output (I/O) pads on each die. Nonetheless, the size ofportable electronic systems such as portable computers, cell phones,PDAs, etc. continues to shrink despite the addition of new features andfunctions. New features and functionalities, such as digital cameras andcamcorders, global positioning systems, and removable memory cards arecontinually being integrated into modern portable and/or high densityelectronic systems. It is desirable to decrease the thickness of thecomponents within portable electronic systems to provide size reductionas well as additional space to add new components.

Although the length and width of portable electronic systems areconstrained by the need to provide a comfortable user interfacetypically including an easy to use keypad and/or an easy to readdisplay, there is a range in the acceptable physical sizes for eachclass of system at any point in time. However, over time, the size ofmost portable electronics systems tends to decrease.

As the manufactured sizes of systems and components continue todecrease, management of energy consumption and heat dissipation becomeincreasingly important both at the level of the system and at theindividual components level. Less space is available for power sourcesand heat dissipation structures. At the level of packaging andinterconnect, this means that strategies and solutions are required toprovide adequate thermal management and to accommodate the stressesgenerated by mismatches in thermal coefficient of expansion (TCE)occurring at the interfaces between components.

Reductions in size and thickness of components are also consistent withperformance improvements due to reductions in signal path lengthsbetween components. Despite increases in the number and density ofinput/output (I/O) pads on each die, the footprint and thickness ofelectronic systems continues to shrink since the individual componentsand/or devices integrated into these systems tend to decrease with eachsuccessive technology generation. Historically, electricalinterconnections were formed as individual components, e.g. contacts,using conventional fabrication technologies such as metal stamping andbending. Using conventional assembly methods, individual contacts areassembled into a finished contactor and/or connector. Conventionalfabrication and assembly methods become increasingly complex andexpensive as the number and density of the contacts increases.

Micro-fabricated spring contacts are capable of overcoming many of thelimitations associated with conventionally fabricated spring contacts.Micro-fabricated spring contacts can be fabricated using a variety ofphotolithography based techniques known to those skilled in the art,e.g. Micro-Electro-Mechanical Systems (MEMS) fabrication processes andhybrid processes such as using wire bonds to create spring contactskeletons and MEMs or electroplating processes to form the completespring contact structure. Arrays of spring contacts can be either bemounted on a contactor substrate by pre-fabricating and transferringthem (either sequentially or in mass parallel) to the contactorsubstrate or by assembling each element of the spring contact arraydirectly on the contactor substrate using a wire bonder along withsubsequent batch mode processes, e.g. electroplating, as disclosed inU.S. Pat. No. 6,920,689 (Khandros et al.), U.S. Pat. No. 6,827,584(Mathieu et al.), U.S. Pat. No. 6,624,648 (Eldridge et al.); U.S. Pat.No. 6,336,269 (Eldridge et al.), U.S. Pat. No. 5,974,662 (Eldridge etal.), U.S. Pat. No. 5,917,707 (Khandros et al.), U.S. Pat. No. 5,772,452(Dozier et al.), and U.S. Pat. No. 5,476,211 (Khandros et al.).

Alternatively, an array of micro-fabricated spring contacts can befabricated directly on a contactor substrate utilizing thick or thinfilm photolithographic batch mode processing techniques such as thosecommonly used to fabricate semiconductor integrated circuits. Numerousembodiments of monolithically micro-fabricated photolithographic springcontacts have been disclosed such as those by Smith et al in U.S. Pat.No. 6,184,699, Mok et al. in U.S. Pat. Nos. 6,791,171 and 6,917,525, andLahari et al in US Patent Pub. No. US-2003-0214045-A1.

Semiconductor wafer probe card assembly systems are used in integratedcircuit (IC) manufacturing and testing to provide an array of springcontact probes for making contact to the electrical interconnection padson each of the semiconductor devices on the wafer. An additionalfunction of probe card assembly systems is to translate electricalsignal paths from the tightly spaced electrical interconnection pads onICs to the coarsely spaced electrical interconnection pads on printedcircuit boards that interface to IC test systems.

Semiconductor wafer probe cards are typically required to accommodateincreases in the density and number of input/output (I/O) pads on eachdie, as well as increases in the diameter of the silicon wafers used inIC fabrication processes. With more die to test per wafer and each diehaving more I/O pads at higher densities, the cost of testing each diebecomes a greater and greater fraction of the total device cost. Thistrend can be minimized or even reversed by reducing the test timerequired for each die or by testing multiple die simultaneously. Ifmultiple die are tested simultaneously, then the requirements forparallelism between the probe tips and the semiconductor wafer and theco-planarity of the probe tips become increasingly stringent since allof the probe tips are required to make good electronic contact at thesame time over a large area on the wafer or the entire wafer in the caseof wafer level test and/or burn-in.

To test more than one die on a semiconductor wafer simultaneously,simultaneous low-resistance electrical contacts must be established withpositionally matching sets of spring contact probes for each die to betested and maintained over a broad temperature range. The more die to betested simultaneously, the greater the degree of parallelism that isrequired between the spring probes and the surface of the semiconductorwafer, to insure that the probe tip “scrub”, and hence electricalcontact, is uniform across the wafer. However, as higher numbers of dieare tested in parallel, the number of simultaneous interconnects fromthe IC to the probe card assembly to the IC tester increases (notassuming pin multiplexing). Since probe tips for contacting the bondingpads on IC wafers require sufficient mechanical force on a perconnection basis to assure a reliable low resistance connection, thetotal force between the probe card assembly and the wafer increases inproportion to the number of connections.

Similar trends are seen in connector, device packaging, and socketingapplications, although specific requirements may vary for each specificapplication. For example, probe scrub damage requirements for probecards which contact the bonding pads, e.g. such as comprising aluminum,gold, copper, solder, etc., on bare die are different those for socketswhich contact the leads, terminals, bumps, etc., e.g. such as comprisinggold, copper, solder, etc., or solder balls, of packaged die or thosefor packaged devices or connectors in which contact is made to contactpads, e.g. such as comprising gold, copper, solder, etc. on a printedcircuit board. Nonetheless, increases in die size and/or the density andnumber of input/output (I/O) pads on each die, and/or use casetemperature extremes tend to drive up the complexity and cost of theelectrical interconnect structures required in all of the aboveapplications. Compensation for lack of co-planarity is also an importantrequirement for connectors, packages and sockets, particularly asconnection areas and die size increases and/or as component thicknessesdecrease.

In some types of IC devices such as memory and microprocessors, diesizes continue to increase whereas for other types of devices such asmixed signal and analog, die sizes have decreased as a result ofnumerous technological advances. Nonetheless, in many cases, decreasesin bond pad sizes, and/or increases in the density and/or number of(I/O) pads is driving the need for cost effective and high performanceminiaturized interconnects for connector, device packaging, andsocketing applications.

Additionally, there is a need for improved methods for providingtemporary electrical connections in which a connection is made for ashort time, for example, in probe card or system testing applications.There is also a need for improvements in demountable electricalconnections in which it is desirable to maintain a reliable connectionfor extended time periods but it may be desired to non-destructivelybeak the connections, for example, in system in package or memory moduleapplications where it is desirable to be able to demount and remount adevice or modular package within a larger system for the purposesincluding but not limited to product development, field or depotupgrade, configuration change, or repair. Additionally, there is a needfor improved methods of providing reliable and low cost permanentelectrical connections.

It would be advantageous to provide micro-fabricated spring contacts ata relatively low cost per contact that maintain low resistanceelectrical connections for a variety of contact geometries andmetallurgies, at high connection densities, over large or small areas,over a wide temperature range, and/or at high frequencies. Suchmicro-fabricated spring contacts would constitute a major technicaladvance.

It would be advantageous to provide micro-fabricated spring contacts ata relatively low cost per contact that maintain low resistanceelectrical connections for a variety of contact geometries andmetallurgies with relatively low contact forces, at high connectiondensities, over large areas, over a wide temperature range, and/or athigh frequencies. Such micro-fabricated spring contacts would constitutea major technical advance.

It would be advantageous to provide contactors incorporatingmicro-fabricated spring contacts at a relatively low cost per contactthat maintain low resistance electrical connections, at high connectiondensities, over large areas, over a wide temperature range, and/or athigh frequencies. Such a contactor would constitute a major technicaladvance.

It would be advantageous to provide contactors incorporatingmicro-fabricated spring contacts at a relatively low cost per contactthat accommodate mismatches in the thermal coefficient of expansion(TCE) between integrated circuit devices and the next level ofinterconnect while providing and efficient means for meeting all thermalmanagement requirements. Such contactors would constitute a furthermajor technical advance.

It would be further advantageous to provide contactors incorporatingmicro-fabricated spring contacts having sufficient mechanical complianceto perform functions including but not limited to accommodating theplanarity requirements of one or more electronic devices with the sameor multiple or varying thicknesses, multiple devices across a wafer, oneor more devices or device types in a single package or module, meetingplanarity compliance requirements for high-density sockets andconnectors, as well providing simultaneous electrical connections andZ-compliance with spring forces appropriate to meet the requirements ofelectronic systems including but not limited to adjustable opticalinterfaces such as auto focus mechanisms for cameras and projectors andother applications in electronic systems including but not limited tocomputers, portable computers, personal digital assistants (PDAs),medical devices, cameras, printers, imaging devices, cell phones, andthe like. Such contactors would constitute a further major technicaladvance.

Furthermore, it would be advantageous to provide means for latchingbetween assembly structures incorporating micro-fabricated springcontacts in temporary, demountable, and permanent applications. Suchassembly structure latching means would constitute a further technicaladvance.

SUMMARY OF THE INVENTION

An improved interconnection system and method is described, such as forelectrical contactors and connectors, electronic device or modulepackage assemblies, socket assemblies and/or probe card assemblysystems. An exemplary interconnection system comprises a first connectorstructure comprising a contactor substrate having a contactor surfaceand a bonding surface, and a set of at least one electrically conductivemicro-fabricated spring contact extending from the contact surface, asecond connector structure having a set of at least one electricallyconductive contact pad located on a connector surface and correspondingto the set of at least one spring contact, and means for movablypositioning and aligning the first connector structure and the secondconnector structure between at least a first position and a secondposition, such that in at least one position, at least one of theelectrically conductive micro-fabricated spring contacts is electricallyconnected to at least one electrically conductive contact pad. Somepreferred embodiments of the connector system comprise temporary,demountable, or permanent latching means between the first connectorstructure and the second connector structure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a detailed schematic diagram of a probe card assembly;

FIG. 2 is a detailed schematic view of a contactor assembly comprisingan array of compliant micro-fabricated spring contacts;

FIG. 3 is a detailed partial cross sectional view of an interposerstructure;

FIG. 4 shows a soldered contactor probe card embodiment having adouble-sided upper interposer;

FIG. 5 shows a soldered contactor probe card embodiment having asoldered upper interposer;

FIG. 6 is a first schematic view of solder ball re-flow contactorconstruction;

FIG. 7 is a second schematic view of solder ball re-flow contactorconstruction;

FIG. 8 is a first schematic assembly view of a high-density connectorhaving fan-out;

FIG. 9 is a second schematic assembly view of a high-density connectorhaving fan-out;

FIG. 10 is a detailed schematic view of a first exemplary embodiment ofassembly latch construction;

FIG. 11 is a detailed schematic view of a second exemplary embodiment ofassembly latch construction;

FIG. 12 is a detailed schematic view of a third exemplary embodiment ofassembly latch construction;

FIG. 13 is a detailed schematic view of a fourth exemplary embodiment ofassembly latch construction;

FIG. 14 is a first schematic assembly view of a high density BGA socketconnector embodiment;

FIG. 15 is a second schematic assembly view of a high density BGA socketconnector embodiment;

FIG. 16 is a detailed partial sectional view of a centered-contactmicro-fabricated spring contact connection for an exemplary high-densityconnector;

FIG. 17 is a detailed partial sectional view of a leading-edgemicro-fabricated spring contact connection for an exemplary high-densityconnector;

FIG. 18 is a detailed partial sectional view of an over-centermicro-fabricated spring contact connection for an exemplary high-densityconnector;

FIG. 19 is a first schematic assembly view of a BGA lattice-socketconnector embodiment;

FIG. 20 is a second schematic assembly view of a high density BGAlattice-socket connector embodiment;

FIG. 21 is a plan view of a first embodiment of a high density BGAlattice-socket connector embodiment;

FIG. 22 is a plan view of a second embodiment of a high density BGAlattice-socket connector embodiment;

FIG. 23 is a first schematic assembly view of a high-density low profileboard-to-board contactor;

FIG. 24 is a second schematic assembly view of a high-density lowprofile board-to-board contactor;

FIG. 25 is a first schematic assembly view of a high-density low profileboard-to-board contactor with fan-out;

FIG. 26 is a second schematic assembly view of a high-density lowprofile board-to-board contactor with fan-out;

FIG. 27 is a first schematic assembly view of a solderless chip mountembodiment;

FIG. 28 is a second schematic assembly view of a solderless chip mountembodiment;

FIG. 29 is a first schematic assembly view of a system in package (SIP)embodiment;

FIG. 30 is a second schematic assembly view of a system in package (SIP)embodiment;

FIG. 31 is a schematic assembly view of Z-compliant connectorconstruction for an exemplary article of manufacture;

FIG. 32 shows a first exemplary embodiment of board to board connectorconstruction;

FIG. 33 shows a second exemplary embodiment of a board to boardconnector construction;

FIG. 34 is a first schematic plan view of a contactor having asymmetricconnections;

FIG. 35 is a second schematic plan view of a contactor having asymmetricconnection arrays;

FIG. 36 is a schematic partial cutaway view of a connector havingasymmetric axial connectivity in a first position;

FIG. 37 is a schematic partial cutaway view of a connector havingasymmetric axial connectivity in a second position;

FIG. 38 is a schematic partial cutaway view of a connector havingasymmetric axial connectivity in a third position; and

FIG. 39 is a schematic partial cutaway view of a connector havingasymmetric axial connectivity in a fourth position.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Introductory disclosure regarding structures, processes and systemsdisclosed herein is seen in: U.S. Provisional Application No.60/136,636, entitled Wafer Interface for High Density Probe Card, filed27 May 1999; U.S. Provisional Application No. 60/146,241, entitledMethod of Massively Parallel Testing of Circuits, filed 28 Jul. 1999;U.S. Provisional Application No. 60/573,541, entitled Quick-Change ProbeChip, filed 20 May 2004; U.S. Provisional Application No. 60/592,908,entitled Probe Card Assembly with Rapid Fabrication Cycle, filed 29 Jul.2004; U.S. Provisional Application No. 60/651,294, entitledNano-Contactor Embodiments for IC Packages and Interconnect Components,filed 8 Feb. 2005; U.S. patent application Ser. No. 10/870,095, entitledEnhanced Compliant Probe Card Systems Having Improved Planarity, USFiling Date 16 Jun. 2004; U.S. patent application Ser. No. 10/178,103,entitled Construction Structures and Manufacturing Processes for ProbeCard Assemblies and Packages Having Wafer Level Springs, US Filing Date24 Jun. 2002; U.S. patent application Ser. No. 09/980,040, entitledConstruction Structures and Manufacturing Processes for IntegratedCircuit Wafer Probe Card Assemblies, US Filing Date 27 Nov. 2001; PCTPatent Application Serial No. PCT/US00/21012, filed 27 Jul. 2000; PCTPatent Application Serial No. PCT/US00/14164, entitled ConstructionStructures and Manufacturing Processes for Integrated Circuit WaferProbe Card Assemblies, US Filing Date 23 May 2000; and U.S. patentapplication Ser. No. 10/069,902, entitled Systems for Testing andPackaging Integrated Circuits, filed 28 Jun. 2002, each of which areincorporated herein in its entirety by this reference thereto.

Micro-fabricated spring contacts, as described previously, may befabricated with variety of processes known to those skilled in the art.Exemplary monolithic micro-fabricated spring contacts may comprisestress metal springs which are photolithographically patterned andfabricated on a substrate using batch mode semiconductor manufacturingprocesses. As a result, the spring contacts are fabricated en masse, andcan be fabricated with spacings equal to or less than that ofsemiconductor bonding pads or with spacings equal to or greater thanthose of printed circuit boards, i.e. functioning as an electricalsignal space transformer.

Monolithic micro-fabricated spring contacts 40, such as seen in FIG. 2,comprise a unitary, i.e. integral construction or initially fabricatedusing planar semiconductor processing methods, whereas non-monolithicspring contacts are typically assembled from separate pieces, elements,or components. Non-monolithic or monolithic micro-fabricated springcontacts can be fabricated on one or both sides of rigid or flexiblecontactor substrates having electrically conductive through-vias andmultiple electrical signal routing layers on each side of the substrateto provide electrically conductive paths for electrical signals runningfrom spring contacts on one side of the substrate to spring contacts orother forms of electrical connection points on the opposite side of thesubstrate through signal routing layers on each side of the substrateand one or more electrically conductive vias fabricated through thesubstrate.

Additionally, optical signals can be transmitted through the contactorsubstrate by fabricating openings of sufficient size through thesubstrate through which the optical signals can be transmitted. Theholes may be unfilled or filled with optically conducting materialsincluding but not limited to polymers, glasses, air, vacuum, etc.Lenses, diffraction gratings and other optical elements can beintegrated to improve the coupling efficiency or provide frequencydiscrimination when desired.

An exemplary monolithic micro-fabricated spring contact comprising astress metal spring is fabricated by sputter depositing a titaniumadhesion/release layer having a thickness of 1,000 to 5,000 angstrom ona ceramic or silicon substrate (approximately 10-40 mils thick) having1-10 mil diameter electrically conductive vias pre-fabricated in thesubstrate. Electrically conductive traces fabricated with conventionalphotolithographic processes connect the spring contacts to theconductive vias and to the circuits to which they ultimately connect. Acommon material used to fabricate stress metal springs is MoCr, howeverother metals with similar characteristics, e.g. elements or alloys, maybe used. An exemplary stress metal spring contact is formed bydepositing a MoCr film in the range of 1-5 μm thick with a built-ininternal stress gradient of about 1-5 GPa/μm. An exemplary MoCr film isfabricated by depositing 2-10 layers of MoCr, each layer about 0.2-1.0μm thick. Each layer is deposited with varying levels of internal stressranging from up to 1.5 GPa compressive to up to 2 GPa tensile.

Individual micro-fabricated stress metal spring contact “fingers” arephotolithographically patterned and released from the substrate, usingan etchant to dissolve the release layer. The sheet resistance of thefinger can be reduced by electroplating with a conductive metal layer(such as copper or gold). The force generated by the spring contact canbe increased by electrodepositing a layer of a material, such as nickel,on the finger to increase the spring constant of the finger. Ininterposer applications (see FIG. 3), the quality of the electricalcontact can be improved by electrodepositing depositing a material, suchas Rhodium 104, onto the tip 86 through a photomask, prior to releasingthe finger from the substrate.

The lift height of the spring contacts is a function of the thicknessand length of the spring and the magnitude of the stress gradient withinthe spring. The lift height is secondarily a function of the stressanisotropy and the width of the spring and the crystal structure andstress in the underlying stress metal film release layer. The springconstant of the spring is a function of the Young's Modulus of thematerial used to fabricate the spring and the length, width, andthickness of the spring. The spring constant of the spring can beincreased by enveloping the springs 40 with a coating of a metalincluding but not limited to electroplated, or sputtered, or CVDdeposited nickel or a nickel alloy, gold, or a palladium alloy such aspalladium cobalt (see FIG. 1).

Methods for depositing coatings of both insulating and conductivematerials are well known to those with ordinary skill in the art andnumerous examples are discussed in the patent applications cited above.The spring constant can be varied over many orders of magnitude bycontrolling the thickness of the deposited coating layer, thegeometrical characteristics of the spring, and the choice of metal andthe thickness and number of coatings. Making the springs thicker bothincreases the contact force and the robustness of the physical andelectrical contact between the spring and its contact pad.

The above teachings describe the manufacture of an exemplary monolithicmicro-fabricated stress metal spring, however, those skilled in the artwill understand that spring contacts having the characteristics requiredto practice the present invention could be designed with many possiblevariations in design and/or fabrication processes. Such variations mayinclude but would not be limited to, for example, choice of processes,process chemicals, process step sequence, base spring metal, releaselayer metal, coating metals, spring geometry, etc. Numerous additionalembodiments of monolithic micro-fabricated spring contacts have beendisclosed such as those by U.S. Pat. No. 6,184,699 (Smith et al.); U.S.Pat. No. 6,791,171 (Mok et al.); U.S. Pat. No. 6,917,525 (Mok et al.);and U.S. Patent Pub. No. US/2003-0214045 A1 (Lahari et al.), each ofwhich is also incorporated herein in its entirety by this referencethereto.

FIG. 1 is a detailed schematic diagram 10 of a probe card assembly 42.As seen in FIG. 1, the probe card assembly 42 comprises a probe cardinterface assembly (PCIA) 41 and a contactor assembly 18, wherein theprobe card interface assembly (PCIA) 41 comprises a motherboard 12having electrical connections 132 (FIG. 4) extending there through, andan integrated contactor mounting system 14. Electrical trace paths 32extend through the motherboard 12, the contactor mounting system 14, andthe contactor assembly 18, to spring contacts, i.e. spring probes 40,such as to establish contacts with pads 28 on one or more ICs 26 on asemiconductor wafer 20. Fan-out 34 may preferably be provided at anypoint for the electrical trace paths 32 in a probe card assembly 42 (orin other embodiments of the systems disclosed herein), such as toprovide transitions between small pitch components or elements, e.g.contactors 18, and large pitch components or elements, e.g. testercontact pads 126 (FIG. 4) on the mother board 12. For example, fan-outmay typically be provided by the mother board 12, the contactor 30, by aZ-block 16, by an upper interface 24 comprising a motherboard Z-Block,or anywhere within the lower interface 22 and/or the upper interface 24.

As seen in FIG. 1, the contactor mounting system 14 typically comprisesa Z-block 16, a lower interface 22 between the Z-block 16 and thecontactor substrate 30, and an upper interface 24 between the Z-block 16and the motherboard 12. In some quick change probe card assemblies 42,the lower interface 22 comprises a plurality of solder bonds 112 (FIG.4). As well, in some quick change probe card assemblies 42, the upperinterface 24 comprises a combination of componentry and connections,such as an interposer 122, e.g. 122 a (FIG. 8) or 122 b (FIG. 5), solderbonds and/or a motherboard Z-block.

FIG. 2 is a detailed schematic view 60 of a contactor assembly 18, inwhich the non-planar portions of compliant spring probes 40 arepreferably planarized and/or plated. As seen in FIG. 2, a contactor 18comprises a contactor substrate 30 having a probing surface 48 a and abonding surface 48 b opposite the probing surface 48 a, a plurality ofspring probes 40 on the probing surface 48 a, typically arranged tocorrespond to the bonding pads 28 (FIG. 1) of an integrated circuit 26on a semiconductor wafer 20, and extending from the probing surface 48 ato define a plurality of probe tips 62, a corresponding second pluralityof bonding pads 64 located on the bonding surface 48 b and typicallyarranged in the second standard configuration, and electricalconnections 66, e.g. vias, extending from each of the spring probes 40to each of the corresponding second plurality of bonding pads 64.

While the contacts 40 are described herein as spring contacts 40, forpurposes of clarity, the contacts 40 may alternately be described ascontact springs, spring probes or probe springs.

Preferred embodiments of the spring contacts 40 may comprise eithernon-monolithic micro-fabricated spring contacts 40 or monolithicmicro-fabricated spring contacts 40, depending on the application.Non-monolithic micro-fabricated spring contacts utilize one or moremechanical (or micro-mechanical) assembly operations, whereas monolithicmicro-fabricated spring contacts exclusively utilize batch modeprocessing techniques including but not limited to photolithographicprocesses such as those commonly used to fabricate MEMs devices andsemiconductor integrated circuits.

In some embodiments of the spring contacts 40, the electricallyconductive monolithically formed contacts 40 are formed in place on thecontactor substrate 30. In other embodiments of the spring contacts 40,the electrically conductive monolithically formed contacts 40 are formedon a sacrificial or temporary substrate 63, and thereafter are removedfrom the sacrificial or temporary substrate 63, e.g. such as by etchablyremoving the sacrificial substrate 63, or by detaching from a reusableor disposable temporary substrate 63, and thereafter affixing to thecontactor substrate 30.

Both non-monolithic and monolithic micro-fabricated spring contacts canbe utilized in a number of applications including but not limited tosemiconductor wafer probe cards, electrical contactors and connectors,sockets, and IC device packages.

Sacrificial or temporary substrates 63 may be used for springfabrication, using either monolithic or non-monolithic processingmethods. Spring contacts 40 can be removed from the sacrificial ortemporary substrate 63 after fabrication, and used in either freestanding applications or in combination with other structures, e.g.contactor substrate 30.

In embodiments of contactor assemblies that are planarized, a plane 72of optimum probe tip planarity is determined for a contactor 18 asfabricated. Non-planar portions of spring contacts 40 located on thesubstrate 30 are preferably plated 60, and are then planarized, such asby confining the probes 40 within a plane within a fixture, and heattreating the assembly. The non-planar portions of the spring probes 40may also be plated after planarization, to form an outer plating layer70.

The contactor assembly 18 shown in FIG. 2 further comprises fan-out 34,such as probe surface fan-out 34 a on the probe surface 48 a of thecontactor substrate 18 and/or rear surface fan-out 34 b on the bondingsurface 48 b of the contactor substrate 18.

FIG. 3 is a partial cross sectional view 78 of an interposer structure80, such as for a dual-sided interposer 80 a, Similar constructiondetails are preferably provided for a single-sided interposer 80 b (FIG.5).

Interposer springs 86, such as photolithographically formed probesprings 86, are generally arranged within an interposer grid array, toprovide a plurality of standardized connections. For example, in thedual-sided interposer 80 a shown in FIG. 4, the interposer springs 86provide connections between a motherboard 12 and a Z-block 16.Similarly, in the single-sided interposer 80 b shown in FIG. 5, theinterposer springs 86 provide connections between a motherboard 12 andan interposer 80 b.

Interposer vias 84 extend through the interposer substrate 82, from thefirst surface 102 a to the second surface 102 b. The interposer vias 84may preferably be arranged in redundant via pairs, such as to increasethe manufacturing yield of the interposer 80, and/or to promoteelectrical conduction, particularly for power traces.

The opposing surfaces 102 a,102 b are typically comprised of a releaselayer 90, such as comprising titanium, and a composite layer 88,92,typically comprising a plurality of conductive layers 88 a-88 n, havingdifferent inherent levels of stress. Interposer vias 84, e.g. such asCuW or gold filled, extend through the central substrate 82, typicallyceramic, and provide an electrically conductive connection between therelease layers 90. The composite layers 88,92 typically comprise MoCr(however other metals with similar characteristics, e.g. elements oralloys, may be used), in which the interposer probe springs 86 arepatterned and subsequently to be later released within a release region100.

A seed layer 94, such as a 0.5 to 1 um thick gold layer, is preferablyformed over the composite layers 88,92. In some embodiments, a tipcoating 104, such as rhodium or palladium alloy, is controllably formedat least over the tips of spring fingers 86, such as to provide weardurability and/or contact reliability. Traces 96, typically comprisingcopper, are selectably formed by plating over the structure 78, asshown, such as to provide reduced resistance. As well polyimide PMIDlayers 98 are typically formed over the structure 78, as shown, todefine the spring finger lift regions. A seed layer 94, such ascomprising a thick layer of gold, remains on the lifted fingers 86, soas to reduce sheet resistance of the fingers 86.

FIG. 4 is a detailed partial schematic view 110 of a probe card assemblysystem 42 a comprising a soldered contactor probe card 18 having adouble-sided upper interposer 80 a. FIG. 5 is a detailed partialschematic view 150 of a probe card assembly system 42 b comprising asoldered contactor probe card embodiment having a single sided upperinterposer 80 b. One or more travel stops 152 can preferably be includedon an interface having compliant interposer spring probes 136, e.g.stress metal spring probes 86 (FIG. 3), to prevent the probes 136 fromdamage, such as if the upper interposer 80 b in FIG. 5 is bottomed outagainst the probe card motherboard 12. The upper interposer 80 b may beplated to increase the probe force of interposer spring probes 136.

Outer alignment pins 130 typically extend from the top stiffener 38through the probe card assembly 42, such as through the probe cardinterface assembly 41. The outer alignment pins 130 engage mechanicalregistration features 134, such as notches, slots, and/or holes, or anycombination thereof, defined in components in the probe card assembly42, such as the motherboard 12 and the Z-block flange 144. The use ofregistration features 134 preferably allows for differences in thermalexpansion between components in the probe card assembly 42, to allowtesting over a wide temperature range.

FIG. 6 is a first schematic view 160 of solder ball re-flow contactorconstruction 162. FIG. 7 is a second schematic view 174 of solder ballre-flow contactor construction 162. Several components and structuresused within probe card assemblies 42 may also be used within otheradvanced assemblies and structures. For example, as seen in FIG. 6 andFIG. 7, a contactor assembly 18 having reflowed solder ball connections112 to a second structure 166, such as substrate 168, e.g. such ascomprising any of ceramic, multi-layer ceramic, glass ceramic, glass,quartz, glass epoxy, FR-4, polyimide, a semiconductor wafer, silicon, aprinted circuit board, one or more flip chip semiconductor devices, oneor more packaged semiconductor devices, a semiconductor integratedcircuit, and a hybrid integrated circuit, preferably provides astructure 162 having a high degree of planarity between the contactorsubstrate 30 and the attached substrate 168, and also has planaritycompliance associated with the spring probes 40 located on the probesurface 48 a of the contactor substrate 30.

As seen in FIG. 6, solder balls 164 are located on electricallyconductive pads 64 on the rear bonding surface 48 b of a probe springsubstrate 30, which are configured to be aligned with electricallyconductive contact pads 170, e.g. gold or solder coated, etc. located ona mating structure 166, such as substrate 168, such as comprising any ofceramic, multi-layer ceramic, glass ceramic, glass, quartz, glass epoxy,FR-4, polyimide, a semiconductor wafer, silicon, a printed circuitboard, one or more flip chip semiconductor devices, one or more packagedsemiconductor devices, a semiconductor integrated circuit, and a hybridintegrated circuit.

The probe spring assembly 18 and the mating structure 166 are thenmovably positioned together 172, such as within an appropriate fixture178. As seen in FIG. 7, heat is then applied to the assembly 162, suchthat the solder balls 164 reflow 176 to form probe assembly solderjoints 112 (FIG. 4, FIG. 5).

As planarity between the contactor substrate 18 and the attachedsubstrate 168 is highly controllable by the fixture 178, the establishedplanarity of the contactor assembly 162 by the bonded solder joints 112provides an assembly which can advantageously be used throughout a widevariety of advanced interconnection structures, such as but not limitedto:

-   -   advanced probe card assemblies for probing fine pitch devices        and/or large area substrates;    -   probe card assemblies for probing wafer level packages, flip        chip devices, chip scale packages, under bump metal, solder,        solder balls, displays, display drivers, area arrays, etc.;    -   miniaturized or high density connector assemblies, e.g. such as        for consumer electronic products, cell phones, PDAs, cameras,        projectors, imaging devices, etc.;    -   socket assemblies, e.g. high density, low insertion force,        solder ball array, land grid array (LGA), etc.;    -   device, partial wafer, and/or full wafer level burn-in        contactors (silicon substrates can be used to provide TCE match        between the contactor and the device under test);    -   single die packages, e.g. wafer level packages (WLP) and/or        singulated die; and/or    -   multi-die packages, e.g. system in a package (SiP) including        embodiments with non-uniform die thicknesses, and/or three        dimensional packages, e.g. stacked die.

Exemplary Latch Assembly Structure having Compliant Spring Interface.

FIG. 8 is a first schematic assembly view of a high-density connector182 a having fan-out 34. FIG. 9 is a second schematic assembly view of ahigh-density connector 182 a having fan-out 34.

As seen in FIG. 8 and FIG. 9, a contactor assembly 18 provideshigh-density connections 214 between a contactor structure 162 and asecondary connector structure 184. The exemplary connector structure 184shown in FIG. 8 and FIG. 9 comprises one or more substrates 186,188having electrically conductive paths 194 defined therethorugh, typicallyhaving a first set of electrically conductive pads 190 which correspondto spring probe contacts 40 on the spring probe assembly 18, and asecond set of electrically conductive pads 196 opposite the connectorstructure 184 from the first set of electrically conductive pads 190. Insome embodiments of the connector structure 184, the second set ofelectrically conductive pads 196 correspond to connectors or contactsfrom an external structure, such as a printed circuit board or a cableconnector.

In some embodiments of the high-density connector 182 a, the connectorstructure 184 comprises a connector body 186,188 having multi-layer thinfilm circuitry and electrically conductive through-vias 194.

As also seen in FIG. 8 and FIG. 9, a contactor assembly 18 comprises atop connector element within a contactor structure 162, such as seen inFIG. 6 and FIG. 7. As well, the probe card assembly 18 seen in FIG. 8and FIG. 9 preferably comprises fan-out 34, such as 34 a,34 b (FIG. 2).Conductive bonds 112 are located between the contactor assembly 118 andthe second structure 166, which preferably comprise solder joints 112.

The high-density connector 182 a seen in FIG. 8 and FIG. 9 comprisesmeans for connection 214 between the contactor structure 162 and thesecondary connector structure 184, wherein establish connections 214 areestablished between the spring probes 40 and the first set ofelectrically conductive pads 190. The means for connection 214preferably comprises one or more latches 212 between the contactorstructure 162 and the secondary connector structure 184, such that thecontactor structure 162 and the secondary connector structure 184 aremovable 208 with respect to one another (FIG. 8), and also provide meansfor fixedly attaching, i.e. latching, when the contactor structure 162and the secondary connector structure 184 are controllably positionedtogether. In some system applications, the latches 212 may provideunlatching, such as for service or for replacement of assemblies. Inother applications, the latches 212 may be considered to be single-uselatches, such as for but not limited to consumer electronics products.

As seen in FIG. 8 and FIG. 9, the connection means 214 may preferablycomprise one or more latches 212 formed by a first latch element 200located on the contactor structure 162, which is matably connectable toa second latch structure 202 located on the secondary connectorstructure 184. The connection means 214 seen in FIG. 8 and FIG. 9 alsopreferably comprises means for alignment 198 between the contactorstructure 162 and the secondary connector structure 184, such as one ormore mechanical alignment guides 198, which may be affixed at a varietyof locations in various embodiments of the connectors 182, such as tothe contactor structure 162, e.g. directly to the contactor assembly 18,or alternately directly to the second structure 166 (FIG. 23,24), or tothe secondary connector structure 184 (FIG. 21, FIG. 22).

High-density connectors 182, such as the high-density connector 182 aseen in FIG. 8 and FIG. 9, may also comprise one or more travel stops204, 206, such as to establish and/or protect the spring probes 40and/or the electrical connections 214 between the spring probes 40 andthe first set of electrically conductive pads 190. In some embodiments,a first set of travel stops 204 acts as means to dampen the latchconnections 212, such as to dampen vibration or movement in the assembly182, i.e. to absorb shock. In some embodiments, the second set of travelstops 206 prevents damage to the spring probes 40 during assembly, use,and/or service.

Exemplary Latch Structures. A wide variety of connection means 214 canbe provided within various embodiments of high-density connectors 182,for latching 212 and/or alignment between contactor structures 162 andsecondary connector structures 184.

FIG. 10 is a detailed schematic view 214 of a first exemplary embodimentof assembly latch construction 212 a. A portion of a contactor structure162, such as a contactor assembly substrate 30, may be fixedly connectedor otherwise attached to one or more alignment guides 198, which maytypically include a first latch element 218 a, e.g. a detent or keep,either integrally or associated with a latch element 216. A portion of asecondary structure 184, such as a substrate 186, may typically includea second latch element 218 b, e.g. a keep or detent. The contactorstructures 162 and secondary connector structures 184 are movable 208 inrelation to each other, e.g. linearly movable on Z-axis 27 (FIG. 1), toestablish a mating latch connection 212 a between the latch elements 218a and 218 b.

FIG. 11 is a detailed schematic view 220 of a second exemplaryembodiment of assembly latch construction 212 b. A portion of acontactor structure 162, such as a contactor assembly substrate 30, maybe fixedly connected or otherwise attached to one or more alignmentguides 198, which may typically include a detent keep assembly, such ascomprising a detent 226, a spring 222, and attachment means 224. Aportion of a secondary structure 184, such as the substrate 186, maytypically include a second latch element 218 b, e.g. a detent, keep,hole, or groove, to attach to the first latch element 218 a. As seen inFIG. 11, the alignment guides 198 may preferably include a ledge detail228 which can act as a travel stop, such as in combination with a lowersurface 187 a of the substrate 186, for latching 212 and/or alignmentbetween contactor structures 162 and secondary connector structures 184.

FIG. 12 is a detailed schematic view 230 of a third exemplary embodimentof assembly latch construction 212 c. One or more alignment guides 198may alternately include first latch element 218 a comprising one or morespring latches 232, fasteners 234, and one or more travel stops 204. Aportion of a secondary structure 184, such as the rear surface 187 b ofthe substrate 186, acts as a second latch element 218 b. As thesecondary structure 184 is moved closer 208 in relation to the contactorstructure 162, as the substrate approaches or compresses the travel stop204, the spring latches 232 catch and fixedly retain the rear surface187 b of the substrate 186.

FIG. 13 is a detailed schematic view 240 of a fourth exemplaryembodiment of assembly latch construction 212 d. A portion of secondarystructure 184, such as substrate 188,186, may be fixedly connected orotherwise attached to one or more alignment guides 198, which maytypically include a first latch element 218 a, e.g. a detent or keep,either integrally or associated with a latch element 216 (FIG. 10). Aportion of a contactor structure 162, such as the substrate 168 or thecontactor substrate 30, may typically include a second latch element 218b, e.g. a keep or detent. The contactor structures 162 and secondaryconnector structures 184 are movable 208 in relation to each other, e.g.linearly movable on Z-axis 27 (FIG. 1), to establish a mating latchconnection 212 d between the latch elements 218 a and 218 b.

Other Advanced Latch Assembly Structures Having Spring ContactInterfaces. FIG. 14 is a first schematic assembly view 250 of ahigh-density connector 182 b, in which the secondary connector structure184 comprises a high density socketed package 252. Package 252 may be aball grid array (BGA), a land grid array (LGA) or other device packagehaving a substrate 186. Electrically conductive pads 190 optionallycomprise a surface coating layer (e.g., gold, solder, etc.). Substrate186 may comprise ceramic, glass ceramic, glass, glass epoxy, FR-4,polyimide, silicon, a printed circuit board, or a flip chipsemiconductor device. FIG. 15 is a second schematic assembly view 264 ofa high-density connector 182 b, in which the secondary connectorstructure 184 comprises a high density socketed package 252. An array254 of solder balls 255 are optionally located on the lower surface ofthe electrically conductive pads 190, which are located directly on thelower surface 187 a adjacent to electrical connection terminals 191. Thehigh-density connector 182 b can be used to serve a wide variety offunctions such as an intermediate connection 259, in conjunction withone or more components 258, e.g. 258 a-258 j, within the package 252,and/or in conjunction with one or more heat sinks 256, e.g. 256 a-256 k,which may preferably include thermal paste junctions 257 to facilitateheat transfer.

In the high-density connector 182 b shown in FIG. 14 and FIG. 15, thecomponents 258 a-258 j may comprise a variety of active and/or passiveelements. In embodiments of the high-density connector 182 b thatinclude one or more heat sinks 256, the heat sinks may be used for heattransfer associated with one or more of the components 258 a-258 j andthe contactor structure 162.

As discussed above, the connection means 214 may preferably comprise oneor more matably connectable latches 212 established between thecontactor structure 162 and the secondary connector structure 184. Theconnection means 214 seen in FIG. 14 and FIG. 15 may also preferablycomprise means for alignment 198 between the contactor structure 162 andthe secondary connector structure 184, such as one or more mechanicalalignment guides 198, which may be affixed at a variety of locations inthe high-density connector 182 b, such as to the contactor structure162, e.g. directly to the contactor assembly 18, or alternately directlyto the second structure 166 (FIG. 23,24), or to the secondary connectorstructure 184 (FIG. 21, FIG. 22).

FIG. 16 is a detailed partial sectional view of a centered-contactspring connection 270 a for an exemplary high density connector 182.FIG. 17 is a detailed partial sectional view of a leading-edge contactspring connection 270 b for an exemplary high density connector 182.FIG. 18 is a detailed partial sectional view of an over-center contact270 b spring connection for an exemplary high density connector 182.

As seen in FIG. 16, a compliant spring 40 extending from a firstconnector structure 162, such as from a contactor substrate 30, makes anelectrical connection 272 with a correspondingly opposing electricallyconductive pad 190 extending from a second connector structure 184, suchas from a substrate 186. As seen in FIG. 16, an electrically conductivesolder ball 255 is located on the electrically conductive pad 190, anddefines a convex surface having a relatively horizontal center 272. InFIG. 16, the first connector structure 162 and the second connectorstructure 184 are associatively positioned 274 such that the tip 62 ofthe compliant spring 272 is aligned with the center 272 of electricallyconductive solder ball 255.

As seen in FIG. 17, the first connector structure 162 and the secondconnector structure 184 are associatively positioned 274 such that thetip 62 of the compliant spring 40 is offset 276 from the center 272 ofelectrically conductive solder ball 255, such that the tip 62 connectsto the electrically conductive solder ball 255 on a leading, i.e. facesurface 277.

As seen in FIG. 18, the first connector structure 162 and the secondconnector structure 184 are associatively positioned 274 such that thetip 62 of the compliant spring 40 is offset 276 from the center 272 ofelectrically conductive solder ball 255, such that the tip 62 connectsto the electrically conductive solder ball 255 on a trailing, i.e. backsurface 279.

As seen in FIG. 16, FIG. 17 and FIG. 18, embodiments of the high densityinterconnectors can preferably provide a wide variety of electricalconnections between the first connector structure 162 and the secondconnector structure 184, such as to prevent damage to solder balls 255and/or compliant springs 40. For example, in probe or connectionembodiments in which probe tips 62 are centered on relatively softsolder balls 255, one or more established connections between a firstconnector structure 162 and a second connector structure 184 may deformthe center of one or more solder balls 255, whereby solder reflow may bedesired to service the second connector structure 184. As seen in FIG.17 and FIG. 18, some preferred high density interconnectors 182 mayalternately provide leading-edge contact spring connections 270 b and/orover-center contact spring connections 270 b, such as to provide a highquality connection over repeated usage.

As well, some preferred high density interconnectors 182 providecontrolled offset of an array of springs 40 associated with an array ofsolder balls 255, e.g. having tips 62 on opposite sides of adjacentsolder balls 255, such as to balance connection forces across aconnector, i.e. to promote self centering and prevent a skewedconnection between the first connector structure 162 and the secondconnector structure 184.

Other preferred embodiments provide alternative arrangements of springcontacts 40 on the contactor substrate 30 that approximately balance thelateral forces on the solder balls 255 generated by the spring contacttips 62 across the connector 182. In some preferred embodiments, onespring contact 40 may be provided for each solder ball 255. Lateralforces across the connector 182 can be minimized and approximatelybalanced by providing approximately equal numbers of spring contacts 40on opposite sides of the solder balls 255, e.g. the leading and trailingedges of every other solder ball 255. For example, at least some of thespring contacts 40 may be located to offset respective lateral forcesapplied to associated solder balls 255, and/or the resulting forcesapplied to the spring contacts 40.

FIG. 19 is a first schematic assembly view 280 of a high-densityconnector 182 c, in which the secondary connector structure 184comprises a high density socketed package 252, and in which thecontactor assembly 18 comprises a plurality of spring contacts 40corresponding to each solder ball connection 255 in a ball grid array254. Package 252 may be a ball grid array (BGA), a land grid array (LGA)or other device package having a substrate 186. In cases where optionalsolder balls 255 are not present, e.g. package 252 is a LGA, springcontacts 40 will directly contact the electrically conductive pads 190.The substrate 186 may comprise ceramic, glass ceramic, glass, glassepoxy, FR-4, polyimide, silicon, a printed circuit board, asemiconductor device package, or a flip chip semiconductor device. FIG.20 is a second schematic assembly view 310 of a high-density connector182 c. The high-density connector 182 c may be configured and functionin a similar manner to the high-density connector 182 b. The preferableinclusion of a plurality of spring contacts 40, e.g. 40 a-40 d can beused for any of reliability, redundancy, applications which requireincreased current or voltage requirements, and mechanical robustness,i.e. providing robust and force balanced connections to optionalelectrically conductive pads 190, solder balls 255, and/or ball gridarray 254.

FIG. 21 is a partial plan view of a first embodiment 316 a of a highdensity spring contact lattice-socket connector 182 c. FIG. 22 is apartial plan view of a second embodiment 316 b of a high density springcontact lattice-socket connector 182 c.

As seen in FIG. 21, in the first embodiment 316 a of the high-densityconnector 182 c, each probe spring set 322 a comprises a plurality ofspring probes 40, e.g. 40 a-40 d, in which the probe spring sets 322 aare aligned in an array of one or more rows 324 and columns 326, tocorrespond to solder balls 255 located on a lower surface 187 a of asecond connector structure 184. Spring probe sets 322 may comprise anyconvenient number of spring probes, such as but not limited to 1, 2, 3and/or 4 springs 40. However, as seen in FIG. 21, spring probes 40 arealso axially aligned 321, 323 to the rows 324 and columns 326respectively, which can limit the density of the connector 182 c and/orthe length of the compliant springs 40.

As seen in FIG. 22, in the second embodiment 316 b of the high-densityconnector 182 c, each probe spring set 322 b also comprises a pluralityof spring contacts 40, e.g. 40 a-40 d, in which the spring contact sets322 b are aligned in an array of one or more rows 324 and columns 326,to correspond to solder balls 255 or electrically conductive pads 190located on a lower surface 187 a of a second connector structure 184.However, as seen in FIG. 22, spring contacts 40 are also diagonallyskewed, e.g. rotated 327 with respect to the rows 324 and/or columns326, which provides an increase in connection density for the connector182 c and/or provides an increased length for the compliant springcontacts 40.

FIG. 23 is a first schematic assembly view 330 of a high-density lowprofile substrate-to-substrate connector 182 d. FIG. 24 is a secondschematic assembly view 350 of a high density low profilesubstrate-to-substrate connector 182 d. A lower substrate 166 and anupper substrate 188, are latchably connected 212, such as betweenstandoffs 332 extending from the secondary connector structure 184, e.g.such as affixed to or through the upper substrate 188, and alignmentguides 198 extending from the contactor structure 162, e.g. such asaffixed to either the contactor assembly 18 or to the lower substratestructure 166. The lower and upper substrates 166 and 168 may compriseany of ceramic, multi-layer ceramic, glass ceramic, glass, quartz, glassepoxy, FR-4, polyimide, a semiconductor wafer, silicon, a printedcircuit board, one or more flip chip ICs, one or more packagedsemiconductor devices, a semiconductor integrated circuit, and a hybridintegrated circuit. As seen in FIG. 24, the standoffs 332 may preferablybe configure to function as travel stops for a latched assembly 182,e.g. 182 d.

FIG. 25 is a first schematic assembly view 360 of a high density lowprofile substrate-to-substrate connector 182 e with fan-out 34. FIG. 26is a second schematic assembly view 380 of a high density low profilesubstrate-to-substrate connector 182 e with fan-out 34. High-densityconnectors 182 inherently provide high-quality high density electricalconnections within a latchable assembly, which can provide fan-out oneither or both sides 162,184 of the latch region 212. Lower and uppersubstrates 166 and 168 may comprise ceramic, glass ceramic, glass, glassepoxy, FR-4, polyimide, silicon, a printed circuit board, one or morepackaged ICs, or one or more flip chip ICs. High-density connectors 182also inherently provide a high degree of planarity within the latchingregion 212, and also provide planarity compliance through the use ofcompliant, i.e. flexible spring probes 40.

Advanced Semiconductor Device Packages. Key problems associated withdevice and wafer level packaging often include:

-   -   Thermal Coefficient of Expansion (TCE) mismatch:    -   Lack of Co-Planarity;    -   Thermal management;    -   High frequency performance; and/or    -   Cost

The use of high-density connectors 182 inherently provides means forcost effective solutions to each of these problems. The X-Y complianceof the spring probes 40, which preferably comprise micro-fabricatedspring contacts, compensates for TCE mismatch between a device and aprinted circuit board, while the Z-compliance of the spring probes 40compensates for lack of co planarity. As well, Z-compliance andcustomizable length springs accommodates chips with different substratethickness, such as for multiple-die packages, e.g. system in package(SiP). Furthermore, multilevel metal can be used to provide controlledimpedance and shielded signal paths. In addition, preferred embodimentsof high-density connectors 182 which utilize photolithographicself-assembling springs have an advantageous cost/performance ratio.

FIG. 27 is a first schematic assembly view 400 of a high-densityconnector 182 f for the solderless mounting of one or more contactorassemblies 18, such as for a contactor assembly that comprises a chipscale package. FIG. 28 is a second schematic assembly view 420 of ahigh-density connector 182 f for the solderless mounting of one or morecontactor assemblies 18. A lower structure 162 b comprises a contactorscale package 18 b located on a structural element 402, such as a planarheat sink, carrier, or surface mount package substrate 402. A secondarystructure 184 includes a substrate 188 comprising any of ceramic,multi-layer ceramic, glass ceramic, glass, quartz, glass epoxy, FR-4,polyimide, silicon, and a printed circuit board. The secondary structure184 also comprises electrically conductive pads 190 on the lower surface187 a. Means are provided for positioning 198 the lower structure 162 band secondary structure 184 in relation to each other, whereby theirposition may be aligned by one or more travel guides 198. The secondarystructure 184 is also latchably attachable 212 to the lower structure162 b, such as by corresponding latch elements 218 a, 218 b.

FIG. 29 is a first schematic assembly view 430 of a high-densityconnector 182 f for a system in package (SIP) embodiment. FIG. 30 is asecond schematic assembly view 450 of a high-density connector 182 f fora system in package (SIP) embodiment. A lower structure 162 c comprisesone ore more contactor scale packages 18, e.g. 18 a-18 j, located on astructural element 432, such as a planar heat sink, carrier, or surfacemount package substrate 432. A secondary structure 184, such ascomprising ceramic, glass ceramic, glass, glass epoxy, FR-4, polyimide,silicon, a printed circuit board 188, one or more packaged ICs, or oneor more flip chip ICs, having electrically conductive contact pads 190,accommodates relative movement in relation to the lower structure 162 c,whereby the movement 208 may be aligned by one or more travel guides198. The secondary structure 184 is also latchably attachable 212 to thelower structure 162 c, such as by corresponding latch elements 218 a,218b.

In a preferred embodiment, contactor scale packages 18 a-18 j compriseintegrated circuit packages which may have the same or differingsubstrate thicknesses 75 a-75 j. In some preferred embodiments,integrated circuit packages 18 a-18 j may comprise non-monolithic ormonolithic micro-fabricated spring contacts to provide compliantelectrical connections circuit board 188. In some preferred embodiments,the spring contact tips 62 are positioned at a standard height from thesupported rear surface 48 b of the integrated circuit devices 18, i.e.adjusted to compensate for differences in thicknesses 75 of theintegrated circuit device substrates 30. In other preferred embodiments,the spring contact tips 62 may are positioned at a fixed height from thecontact surface 48 a of the integrated circuit device substrates 30,i.e. the compliance of the spring contacts 40 provide compensation fordifferences in thicknesses of the integrated circuit device substrates30.

Alternate Advanced Assembly Structures. FIG. 31 is a schematic assemblyview 460 of Z-compliant connector construction for an exemplary articleof manufacture 462, such as for but not limited to a camera, a videocamera, a personal digital assistant (PDA), a solid state music player,e.g. an MP3 or an enhanced iPod, or for a multi-function device.

In the exemplary article of manufacture 462, a MEMS Z-Actuator 472,having probe springs 40, is slidably movable 463 on one or more actuatorstators 468. An image sensor, e.g. CCD, chip 474 is mounted, e.g.surface mounted, to the opposing side of the MEMS Z-Actuator 472. Theactuator stators 468 are affixed with respect to a printed circuit board466. The printed circuit board 466 is affixed with respect to at thecase structure 464 of the article 462. For an article of manufacture 462comprising a camera, a lens 478 is typically located such that light 484associated with a captured image 481 is controllably captured, i.e.allowed to enter and sensed by the image sensor 474, such as by ashutter 483. An auto focus light source 480 and light detector 482 mayalso be included, such that emitted light 486 is reflected and sensed asan input to a control 490.

In the exemplary article of manufacture 462 seen in FIG. 31, the MEMSZ-Actuator 472 is slidably movable 463 in the Z-direction 27 (FIG. 1) onthe actuator stators 468, such as to any reference plane between andincluding a first position 465 a and a second position 465 b, whereincompliant contactor array 470, comprising spring contacts 40 canpreferably provide compliant electrical contacts to the printed circuitboard 466 throughout the range of motion 465 a,465 b.

The effective focal plane 467 from the lens 478 to the image sensor 474is therefore controllably variable at any point between and includingthe first position 465 a and the second position 465 b. For example,during auto focus operation of the camera 462, emitted light 486 fromthe auto focus light source 480 is reflected off a subject SBJ andsensed by the light detector 482, which acts as an input for control490. Based upon the auto focus input, the controller 490 moves the MEMSactuator 472 at any point between and including a first position 465 aand a second position 465 b, to provide a desired focal length 467. Animage 481 is then typically controllably captured, such as by controlledopening of a shutter 483, and stored to a memory 492, which can then bedownloaded or otherwise transferred, e.g. such as by a removable memoryelement 494.

FIG. 32 is a detailed schematic view 500 of first exemplary board toboard high-density connector 182 i, such as to provide any of areleasable or permanent connection between a high cost printed wiringboard 168 and a low cost printed wiring board 502. FIG. 33 is a detailedschematic view 550 of secondary exemplary board to board high-densityconnector 182 j, such as to provide any of a releasable connection orpermanent connection between a package substrate 552 and a low costprinted wiring board 502.

The exemplary secondary connector assembly 184 seen in FIG. 32 and FIG.33 comprises electrical connections 506, such as but not limited tosolder ball connections 506, e.g. such as provided by reflow 176,between a printed circuit board 502 and a lower connector substrate 504.The lower connector substrate 504 further comprises contact pads 512 onthe upper surface, electrically conductive vias 508 extending throughthe lower connector substrate 504, and lower contacts 190, forconnection with one or more corresponding probe springs 40 extendingfrom the contactor assembly 18.

The exemplary latches 212 shown in FIG. 32 and FIG. 33 comprise one ormore alignment guides 198, which latchably mate 218 a,218 b, e.g. FIG.10-FIG. 13, to one or more corresponding latches 516, which maypreferably further function as travel stops for the assembly. Theassembly may also preferably comprise dedicated travel stops 520, suchas extending from the lower connector substrate 504.

Contactors Having Asymmetric Connectivity. Some embodiments of theconnector 182 provide asymmetric connectivity, which is well suited fora large number of applications, such as but not limited to accessingalternate pathways, connection to different circuits and/or devices,and/or providing alternate connection redundancy.

FIG. 34 is a first schematic plan view 600 a of a connector 182 havingasymmetric connections. FIG. 35 is a second schematic plan view 600 b ofa connector 182 having asymmetric connection arrays.

As seen in FIG. 34 and FIG. 35, a first exemplary structure 162, such asdescribed above, comprises a plurality of sides 602 a, 602 b, 602 c and602 d. Similarly, the second exemplary structure 184, such as describedabove, comprises a plurality of sides 606 a, 606 b, 606 c and 606 d. Thefirst structure 162 may also comprise an orientation detail 604, and thesecond structure 184 may also comprise an orientation detail 608.

The first exemplary structure 162 seen in FIG. 34 and FIG. 35 maycomprise an asymmetric array 611 of first connective paths 612, and/orthe second structure 184 may comprise an asymmetric array of secondconnective paths 610.

As seen in FIG. 34, when the exemplary connector 182 is oriented in afirst position 600 a, wherein the first exemplary structure 162 and thesecond structure 184 are oriented such that side 602 a is aligned with606 a, e.g. when details 604,608 are aligned, an array 614 a ofconnections 214 (FIG. 9) is defined for first connective paths 612 thatcoincide with second connective paths 610.

As seen in FIG. 35, the first exemplary structure 162 and the secondstructure 184 can be selectably oriented with respect to each other,e.g. by rotating the connectors 162,184 with respect to each other aboutthe Z-axis 27, i.e. in a plane defined by the X-axis 23 and the Y-axis25. For example, when the exemplary connector 182 is oriented in asecond position 600 b, wherein the first exemplary structure 162 and thesecond structure 184 are oriented such that side 602 a is aligned with606 c, an alternate array 614 b of connections 214 is defined for firstconnective paths 612 that coincide with second connective paths 610.

The exemplary square connector 182 seen in FIG. 34 and FIG. 35 maypreferably include more than one asymmetric position, such as to rotateninety degrees in any direction, e.g. wherein side 602 a is alignedsecond connector sides 606 b or 606 d, to provide alternate arrays 614of connections 214.

While the exemplary connector 182 seen in FIG. 34 and FIG. 35 is shownas a square connector 182, e.g. comprising square symmetry between afirst connector structure 162 and a second connector structure 184, awide variety of component shapes and geometric symmetries may be used,such as to provide asymmetric connections 214, such as but not limitedto symmetries based on rectangles, alternate polygons, and/or evencylinders with keyed, i.e. grooved mating details.

As well, some embodiments of the connector 182 provide axial asymmetricconnectivity which can also be adapted for a wide variety ofapplications, such as but not limited to accessing alternate pathways,connection to different circuits and/or devices, and/or providingalternate connection redundancy.

For example, for a high-density interconnection assembly 182 havingaxial positional movement 208 in regard to a Z-axis 27, axial movement208 can define an amount of insertion between a first connectorstructure 162 and a second connector structure 184. Axial movement 208in relation to an insertion axis may define any relative movementbetween a first connector structure 162 and a second connector structure184, such as between at least two positions, wherein positions maydefine positions of separation between springs 40 and opposing contacts90, position of first contact for one or more springs 40, positions ofcompliant, i.e. compressed contact, and/or positions of contact limits,such as determined by one or more travel stops, latches, and/or detents.

Some embodiments of high-density interconnection assemblies 182 providesprings 40 having relatively similar height 702 (FIG. 36), and opposingpads 90 having relatively similar height 704 (FIG. 36), such as toprovide a plurality of connections between entire arrays of opposingsprings 40 and electrically conductive pads 190.

As well, alternate embodiments of high-density interconnectionassemblies 182 provide springs 40 having different heights 702, and/oropposing electrically conductive pads 190 having different heights 704,such as to provide differing arrays of connections between entire arraysof opposing springs 40 and electrically conductive pads 190, based uponaxial positioning relation to an insertion axis, e.g. Z-axis 27. Springheight 702 can be varied in a number of ways known to those skilled inthe art, including, for example, by varying the design length of thesprings on the substrate as defined by photolithography. Pad height 704can varied in a number of ways known to those skilled in the art, forexample, by varying the thickness of metal plated onto the pad supportsubstrate 186,188.

FIG. 36 is a schematic partial cutaway view of a connector 182 havingasymmetric axial connectivity in a first position 700 a. FIG. 37 is aschematic partial cutaway view of a connector 182 having asymmetricaxial connectivity in a second position 700 b. FIG. 38 is a schematicpartial cutaway view of a connector 182 having asymmetric axialconnectivity in a third position 700 c. FIG. 39 is a schematic partialcutaway view of a connector 182 having asymmetric axial connectivity ina fourth position 700 d.

As seen in FIG. 36, the first connector structure 162 typicallycomprises a contactor substrate 30 having compliant springs 40, e.g. 40a,40 b, extending away from the substrate 30 toward the second connectorstructure 184. The compliant springs 40 shown in FIG. 36 define a formedspring height 702, such as relative either to the substrate 30 or to oneof the layers, e.g. release layer 90 (FIG. 3), upon which they areformed. As seen in FIG. 36, the spring height 702 a for springs 40 a isless than the spring height 702 b for a spring 40 b.

As also seen in FIG. 36, the second connector structure 184 typicallycomprises a board substrate 186,188 having electrically conductive pads90 extending away from the substrate 186,188 toward the first connectorstructure 162. The pads 90 shown in FIG. 36 define a pad height 704,typically relative to the substrate 186,188. As seen in FIG. 36, padheight 704 a for pads 92 a is more than the pad height 704 b for aspring 92 b.

The difference in heights 702 and 704 inherently provides means forasymmetrical contacts with respect to an insertion axis, e.g. Z-axis 27.As seen in FIG. 37, at a position 700 b, wherein a first distance 707 ais defined between the contactor substrate 30 and the substrate 186,188,the spring 40 b is electrically connected to an opposing 90 b, whilesprings 40 a are not electrically connected to corresponding pads 92a,92 b. As seen in FIG. 38, at a position 700 c, the spring 40 b ispartially compressed and is electrically connected to an opposing pad 90b, while a second pad 90 b is electrically connected to an opposingspring 40 a, and while pad 92 b is not electrically connected to itscorresponding pad 40 a. As seen in FIG. 38, at a position 700 d, thespring 40 b is further compressed and is electrically connected to anopposing pad 90 b, the second pad 90 b is electrically connected to anopposing compressed spring 40 a, and pad 92 b is electrically connectedto its corresponding pad 40 a.

The connectors 182 having asymmetric axial connectivity seen in FIGS.36-39 can therefore preferably provide one or more contactor states atdifferent distances 707, e.g. 707 a-707 d, and can be used for a widevariety of applications, such as to connect one or more connectedcircuits based upon position 700, and/or to provide sensing or control,such as to sense a limit for insertion travel 208.

High density connectors 182 utilize arrays of micro-fabricated springcontacts 40, fabricated on a substrate 18, to provide simultaneouselectrical contact between two objects, such as but not limited tocomponents, devices, systems, sub-systems, and/or substrates. Somepreferred embodiments of the connectors 182 can be utilized for spaceconfined applications, such as but not limited to cell phones, personaldigital assistants (PDAs), computers, portable computers, medicaldevices, cameras, video cameras, printers, imaging devices, digitalmedia players, and/or other portable electronic systems where it isdesired to minimize the space required in the X, Y, or Z directions23,25,27 or any combination thereof.

The force versus displacement characteristics of the springs 40 arecontrolled by the design of the spring 40, and multiple types of springcharacteristics can be provided in a single device, e.g. 18, since thesprings 40 are batch processed with photolithographic chip processingtechnologies. Force can be increased by adding plated metal layers, e.g.such as one or more layers (68,70 (FIG. 2); 104 (FIG. 3)) or decreasedby making the springs 40 longer, narrower, or thinner. Low force springs40 can maintain electrical contact, while imparting minimal loading toexternal actuation systems.

Some embodiments of high density connectors 182 comprise arrays ofmicro-fabricated spring contacts, fabricated on a substrate, to providesimultaneous electrical contact between two objects (includingcomponents, devices, systems, sub-systems, substrates, etc.) inapplications where it is desired to maximize connection density orminimize the space required in the X, Y, or Z directions or anycombination thereof and where it is desired to interconnect componentswith IC bond bad spacings to components with printed circuit boardspacings.

As well, some embodiments of high density connectors 182 comprise arraysof micro-fabricated spring contacts fabricated on multiple integratedcircuit devices, to provide electrical contact between the integratedcircuit devices and a common support substrate and thermal contact witha common heat sink wherein each device may have different thicknessesand/or coefficients of thermal expansion.

Furthermore, some embodiments of high density connectors 182 comprisearrays of micro-fabricated spring contacts 40, fabricated on asubstrate, e.g. contactor substrate 30, at very high density to providea small area, thin and inexpensive electrical connector between twoobjects (including components, devices, systems, sub-systems, and/orsubstrates).

In addition, some embodiments of high density connectors 182 comprisearrays of micro-fabricated spring contacts 40, fabricated on one side ofa flexible thin substrate, e.g. contactor substrate 30, at very highdensity and the other side of the substrate 30 at a low density, so asto provide a space transforming function and thus to provide aninexpensive electrical connector between two objects, e.g. such as butnot limited to components, devices, systems, sub-systems, and/orsubstrates, having widely varying electrical connection pitches.

As described above, some embodiments of high density connectors 182comprise arrays of micro-fabricated spring contacts 40, fabricated on asubstrate 30, to provide simultaneous electrical contact between twoobjects, e.g. such as but not limited to components, devices, systems,sub-systems, and/or substrates, over a range of distances between theobjects and/or during relative motion of the objects with respect toeach other.

In some embodiments of the present invention, the tips 62 of the springcontacts 40 can be soldered or otherwise affixed to the targetedelectrical contact pads. Affixing the probe tips 62 to the electricallyconductive pads 190 eliminates tip sliding and resists X, Y, and Zmotion, however with an appropriate applied force, the position ororientation of one object with respect to the other can be changed andwhen the applied force is removed, the objects reposition themselves tothe initial position assuming that all displacements have been smallenough to avoid plastic deformation of the springs. With the tips of thespring contacts affixed to a support substrate, the spring contacts arecapable of supplying both a pushing and a pulling force against externalactuators.

In an additional aspect of the present invention, more than one springcontact design may be employed to provide springs with differingcharacteristics to carry out differing functions. In an exemplaryembodiment, one type spring contacts can be designed and positioned toprovide electrical contacts at specific locations whereas other typessprings can be designed and positioned at other locations to providemechanical forces to perform separate functions. This is possible sincethe mechanical characteristics of the springs can be changed by changingtheir length, width or their position yet since all of the springs arefabricated simultaneously, multiple types of springs can be providedwith the same fabrication steps.

The aspects of the invention described above can be used individually orin combinations to create alternative embodiments of the presentinvention. In the foregoing examples, the term substrate is intended tomean a thin or thick, inflexible or flexible, hard or soft insulatingmaterial that is chosen to be best suited for a particular application.Substrates are typically fabricated from single or multi-layer ceramic,glass ceramic, glass, quartz, semiconductors such as silicon, and/orpolymers such as polyimide or printed circuit board materials, e.g.FR-4. Substrates may also be complete integrated circuits or hybridintegrated circuits. Substrates may be sacrificial or temporary whereinsprings are fabricated, using either monolithic or non-monolithicprocessing methods, on a fabrication substrate. Springs can be removedfrom the fabrication substrate after fabrication and used in either freestanding applications or in combination with other structures.

System Advantages. The use of high-density connectors 182 inherentlyprovides improvements for several areas of connector design, such as:

-   -   Thermal Coefficient of Expansion (TCE) mismatch:    -   Lack of Co-Planarity;    -   Thermal management;    -   High frequency performance; and/or    -   Cost

The X-Y compliance provided by spring probes 40 in high-densityconnectors 182, which preferably comprise micro-fabricated springcontacts 40, compensates for TCE mismatch between a first connectorassembly 162 and a second connector assembly 184, such as between adevice and a printed circuit board, while the Z-compliance of the springprobes 40 compensates for lack of co planarity.

As well, Z-compliance and customizable length springs 40 accommodatechip packages 18 with different contactor scale package substratethickness 75, such as for multiple-die packages, e.g. system in package(SiP). Furthermore, multilevel metal can be used to provide controlledimpedance and shielded signal paths. In addition, preferred embodimentsof high-density connectors 182 which utilize photolithographicself-assembling springs have an advantageous cost/performance ratio.

In addition, the use of one or more latches 212 between a firstconnector assembly 162 and a second connector assembly 184 provides botha mechanical connection between the assemblies 162,184, as well as acontrolled connection environment, such as between the compliant springprobes 40 and opposing electrically conductive pads 190.

The use of high-density connectors 182 lowers the cost of ownership formany high-density assemblies, by allowing users to easily changecontactor assemblies 18 and associated connector assemblies 162, such asby disconnecting the latches 212. The high-density connectors 182 allowa trained user or field service engineer to quickly change either thefirst connector assembly, i.e. contactor 162 and/or a second connectorassembly 184, such as at a customer site.

As well, customers can keep an inventory of first connector assemblies162 and/or second connector assemblies 184 on hand, and swap firstconnector assemblies 162 and/or second connector assemblies 184 asneeded, instead of an entire high density electronic assembly. Thiscapability minimizes downtime related to contactor issues, such as forregular scheduled cleaning, tip wear, tip failure, and/or unexpected tipcontamination.

The disclosed methods of design and fabrication associated with themanufacture of high density connectors 182 reduce or eliminate the needfor planarity adjustments at final assembly.

High-density connectors 182 comprise components with mechanical surfacesthat are sufficiently flat and parallel to one another, that enable themto act as reference surfaces for other components either within theprobe card assembly system, or that interface to the probe card assemblysystem. As well, the high density connectors 182 and associatedprocesses maintain low resistance electrical connections to a deviceunder test at either elevated or depressed operating temperatures.

Furthermore, high-density connectors 182 have relatively flat andparallel component surfaces, which more evenly distributes andvertically transmits the high forces associated with high I/O countconnectors, to reduce peak-to peak mechanical deflections within theconnector system, wherein the forces are generated either by the variousspring pre-loading mechanisms or by the compression of the spring probesduring connection.

In addition, the high-density connectors 182 have components withimproved flatness and parallelism that can rest against each other, thatenable pre-aligned, easy to replace components and sub-assemblies.Relatively flat and parallel surfaces and probe tip arrays havingsmaller deviations from co-planarity reduce the need for planarityadjustment. Additionally, the use of relatively flat and parallelreference surfaces enables the use of very low force interposers ifused, e.g. 0.05 g to 5 g per contact, to make low resistancehigh-density electrical connections over large areas, e.g. 1,000 sq cmfor 300 mm wafers. Furthermore, low force interposers combined with flatand parallel reference and support surfaces enable simpler methods ofclamping and achieving and maintaining planarity. Alternatively, largearea components such as mother boards, Z-blocks, etc. with flat surfacesenable the use of vacuum actuated systems to achieve high levels ofsurface parallelism. Additionally, large area solid electrical interfaceconnections fabricated with materials such as solder, gold wire bondbumps, plated bumps, or adhesives all have higher manufacturing yieldsand perform better and more reliably with flatter and more parallelinterconnection support surfaces.

As well, time is often critical factor for users of high-densityconnector assemblies 182, such as semiconductor manufacturers andtesters. For example, conventional probe card assemblies typicallycomprise one or more key components that have long lead times, such asfor multilayered ceramic components. As conventional assembly structuresand manufacturing methods include such long lead time components, theresulting fabrication cycle for one or more assemblies is long.

In contrast, high-density connector assemblies 182 have improved, i.e.rapid, fabrication cycles, for which portions of the probe card assemblycan be fabricated, assembled, and/or pre-planarized, while long-leadlead time components, such as complex, custom, or semi-customcomponents, are readily mountable and/or remountable from the othercomponents and assemblies.

The methods according to the present invention adjust for the planaritydifferences during high density connector assembly fabrication, byreducing or eliminating requirements for applying pressure to flexibleconnectors and/or adjusting linear actuators. The methods according thepresent teachings include creating co-planar arrays of probe springsusing two or more plating steps and planarizing a contactor assembly bycausing variations in solder joint height to compensate for planardifferences between the sub-components. Both manufacturing methodscreate flat reference tooling surfaces and use vacuum or other means tohold components under assembly flat against the reference toolingsurfaces. In the case of probe springs, the first layer of plating isapplied and the tips are made co-planar by heating while holding thetips against a reference tooling surface prior to completing theadditional plating which is required to provide adequate probing forceto insure a reliable electrical contact over an acceptable cycle life.In the case of the mother board to probe spring assembly, thesecomponents can be pulled flat to a reference tooling surface parallel tothe WRS and solder can be reflowed to retain the parallelism.

The invention also utilizes standard components for both reducingmanufacturing cost and manufacturing time.

Although high-density interconnect systems having spring probes withimproved co-planarity and parallelism, and methods for manufacturing aredescribed herein in connection with integrated circuit test probes,probe cards, electrical assemblies, articles of manufacture, and/orpackages, the system and techniques can be implemented with a widevariety of devices, such as interconnections between integrated circuitsand substrates within a wide variety of electronic components ordevices, burn-in devices and MEMS devices, or any combination thereof,as desired.

As well, those knowledgeable and skilled in the art will readilyappreciate that various alternative types of probe tips could besubstituted for the stress metal spring (SMS) probe tips describedherein and that therefore the teachings relating to the methods andapparatus of the present invention should not be interpreted as beinglimited to the use of the SMS probe tips described herein.

Accordingly, although the invention has been described in detail withreference to a particular preferred embodiment, persons possessingordinary skill in the art to which this invention pertains willappreciate that various modifications and enhancements may be madewithout departing from the spirit and scope of the claims that follow.

1. An apparatus, comprising: a first connector structure comprising atleast one contactor substrate having a contact surface and a bondingsurface, the at least one contactor substrate comprising an array of atleast one electrically conductive monolithically formed micro-fabricatedstress metal spring contact located on and extending from the contactsurface; a second connector structure comprising a substrate having afirst connector surface and a second surface opposite the connectorsurface, and comprising an array of at least one electrically conductivecontact pad located on the first connector surface and corresponding tothe array of at least one electrically conductive spring contact, and anarray of at least one electrically conductive path extending from thefirst connector surface to the second surface; means for any of movablypositioning and aligning the first connector structure and the secondconnector structure between at least a first position and a secondposition with respect to each other; and means for mechanically affixingthe first connector structure and the second connector structure,wherein the affixing means comprises at least one latchable interfacebetween the first connector structure and the second connectorstructure.
 2. The apparatus of claim 1, wherein the means for any ofmovably positioning and aligning the first connector structure and thesecond connector structure comprises means for axially positioning anyof the first connector structure and the second connector structure. 3.The apparatus of claim 1, wherein the affixing means is any oftemporary, demountable, and permanent.
 4. The apparatus of claim 1,wherein the latchable interface comprises at least one latch elementassociated with any of the first connector structure and the secondconnector structure.
 5. The apparatus of claim 4, wherein the at leastone latch element comprises any of a groove, a ridge, a detent, aspring, a fastener, a hole, a catch, and any combination thereof.
 6. Theapparatus of claim 1, further comprising: a travel stop associated withand extending from any of the first connector structure and the secondconnector structure and toward the other of the first connectorstructure and the second connector structure.
 7. The apparatus of claim1, wherein the at least one contactor substrate further comprises anarray of electrically conductive contacts on the bonding surface, and anarray of at electrically conductive paths extending from respectiveelectrically conductive spring contacts to corresponding electricallyconductive contacts.
 8. The apparatus of claim 7, wherein the firstconnector structure further comprises a board substrate having a firstside and a second side opposite the first side, and a plurality ofelectrical contacts located on the first side; and at least oneelectrical connection between the board substrate and at least onecontact located on the bonding surface of the spring contact substrate,the electrical connection located between at least one of the electricalcontacts on the first side of the board substrate and the at least onecontact located on the bonding surface of the spring contact substrate.9. The apparatus of claim 8, wherein the electrical connection betweenthe board substrate and the at least one contact located on the bondingsurface of the spring contact substrate comprises any of a solder balland a solder joint connection.
 10. The apparatus of claim 1, wherein inat least one of any of the first position and the second position, atleast one electrically conductive spring contact is electricallyconnected to at least one electrically conductive contact pad.
 11. Theapparatus of claim 10, further comprising an article of manufactureassociated with any of the first connector structure and the secondconnector structure, the article of manufacture having a plurality ofoperating states, wherein at least one operating state of the article ofmanufacture is at least partially associated with the respectiveposition of the first connector structure and the second connectorstructure relative to each other.
 12. The apparatus of claim 1, whereinin at least the first position and the second position, at least oneelectrically conductive spring contact is electrically connected to atleast one electrically conductive contact pad.
 13. The apparatus ofclaim 1, wherein fan-out is provided by any of the first connectorstructure and the second connector structure; wherein for the firstconnector structure, the at least one contactor substrate furthercomprises an array of electrically conductive contacts on the bondingsurface, and an array of electrically conductive paths extending fromrespective electrically conductive spring contacts to correspondingelectrically conductive contacts, wherein the distance between at leasttwo electrically conductive spring contacts on the contact surface isless than the distance between any of the electrically conductivecontacts on the bonding surface; and wherein for the second connectorstructure, the array of at least one electrically conductive contact padon the first connector surface of the second connector structurecomprises a plurality of electrically conductive contact pads, whereinthe second connector structure further comprises an array of electricalcontacts on the second surface, wherein that the distance between atleast two electrically conductive contact pads on the first connectorsurface is less than the distance between any of the electrical contactson the second surface.
 14. The apparatus of claim 1, wherein the secondconnector structure further comprises an array comprising a solder balllocated on at least one of the electrically conductive contact pads onthe first connector surface.
 15. The apparatus of claim 14, wherein thespring contacts define a leading tip; wherein when the first connectorstructure and the second connector structure are in at least oneposition proximate to each other, the spring contacts are axiallypositioned with respect to the solder balls.
 16. The apparatus of claim15, wherein the solder balls define a convex contact surface, andwherein the leading tips are aligned with any of an inclined leadingface, a horizontal center face and an inclined trailing face of thesolder balls.
 17. The apparatus of claim 16, wherein at least two of thespring contacts are located to offset respective lateral forces appliedto associated solder balls.
 18. The apparatus of claim 16, wherein atleast two spring contacts are associated with each solder ball.
 19. Theapparatus of claim 18, wherein at least two of the spring contacts arelocated to offset respective lateral forces applied between theirrespective leading tips and associated solder balls.
 20. The apparatusof claim 1, wherein the second connector structure further comprises atleast one element located on the back surface of the substrate, theelement comprising any of a second substrate, a component, a heat sink,and a connector.
 21. The apparatus of claim 1, further comprising: atleast one structural element; wherein the bonding surface of the atleast one contactor substrate is in contact with the structural element;and wherein each of the at least one contactor substrate comprises apackage assembly.
 22. The apparatus of claim 21, wherein the structuralelement comprises any of a heat sink, a carrier, and a surface mountpackage.
 23. The apparatus of claim 1, wherein the spring contactscomprise any of flexible springs, compliant springs, and elongateresilient probe elements.
 24. The apparatus of claim 1, wherein thecontactor substrate comprises any of ceramic, multi-layer ceramic, glassceramic, glass, quartz, glass epoxy, FR-4, polyimide, a semiconductorwafer, silicon, a printed circuit board, one or more flip chipsemiconductor devices, one or more packaged semiconductor devices, asemiconductor integrated circuit, and a hybrid integrated circuit. 25.The apparatus of claim 1, wherein the substrate of the second connectorstructure comprises any of ceramic, multi-layer ceramic, glass ceramic,glass, quartz, glass epoxy, FR-4, polyimide, a semiconductor wafer,silicon, a printed circuit board, one or more flip chip semiconductordevices, one or more packaged semiconductor devices, a semiconductorintegrated circuit, and a hybrid integrated circuit.
 26. The apparatusof claim 1, wherein the array of electrically conductive monolithicallyformed micro-fabricated stress metal spring contacts is either formed onany of a sacrificial substrate and a temporary substrate and thereafterremoved and affixed to the contactor substrate; or formed in place onthe contactor substrate.
 27. An apparatus, comprising: a first connectorstructure comprising at least one contactor substrate having a contactsurface and a bonding surface, the at least one contactor substratecomprising an array of at least one electrically conductivemonolithically formed micro-fabricated stress metal spring contactlocated on and extending from the contact surface, wherein the springcontacts define a leading tip; a second connector structure comprising asubstrate having a first connector surface and a second surface oppositethe connector surface, and comprising an array of at least oneelectrically conductive contact pad located on the first connectorsurface and corresponding to the array of at least one electricallyconductive spring contact, an array of at least one electricallyconductive path extending from the first connector surface to the secondsurface, and an array comprising solder balls located on at least one ofthe electrically conductive contact pads on the first connector surface,wherein the solder balls define a convex contact surface; and means forany of movably positioning and aligning the first connector structureand the second connector structure between at least a first position anda second position with respect to each other; wherein when the firstconnector structure and the second connector structure are in at leastone position proximate to each other, the spring contacts are axiallypositioned with respect to the solder balls, wherein the leading tipsare aligned with any of an inclined leading face, a horizontal centerface and an inclined trailing face of the solder balls.
 28. Theapparatus of claim 27, wherein at least two of the spring contacts arelocated to offset respective lateral forces applied to associated solderballs.
 29. The apparatus of claim 27, wherein at least two springcontacts are associated with each solder ball.
 30. The apparatus ofclaim 29, wherein at least two of the spring contacts are located tooffset respective lateral forces applied between their respectiveleading tips and associated solder balls.
 31. The apparatus of claim 27,wherein the means for any of movably positioning and aligning the firstconnector structure and the second connector structure comprises meansfor axially positioning any of the first connector structure and thesecond connector structure.
 32. The apparatus of claim 27, furthercomprising: means for mechanically affixing the first connectorstructure and the second connector structure.
 33. The apparatus of claim32, wherein the affixing means is any of temporary, demountable, andpermanent.
 34. The apparatus of claim 27, further comprising: a travelstop associated with and extending from any of the first connectorstructure and the second connector structure and toward the other of thefirst connector structure and the second connector structure.
 35. Theapparatus of claim 27, wherein the at least one contactor substratefurther comprises an array of electrically conductive contacts on thebonding surface, and an array of electrically conductive paths extendingfrom respective electrically conductive spring contacts to correspondingelectrically conductive contacts.
 36. The apparatus of claim 35, whereinthe first connector structure further comprises a board substrate havinga first side and a second side opposite the first side, and a pluralityof electrical contacts located on the first side; and at least oneelectrical connection between the board substrate and at least onecontact located on the bonding surface of the spring contact substrate,the electrical connection located between at least one of the electricalcontacts on the first side of the board substrate and the at least onecontact located on the bonding surface of the spring contact substrate.37. The apparatus of claim 36, wherein the electrical connection betweenthe board substrate and the at least one contact located on the bondingsurface of the spring contact substrate comprises any of a solder balland a solder joint connection.
 38. The apparatus of claim 27, wherein inat least one of any of the first position and the second position, atleast one electrically conductive spring contact is electricallyconnected to at least one electrically conductive contact pad.
 39. Theapparatus of claim 38, further comprising an article of manufactureassociated with any of the first connector structure and the secondconnector structure, the article of manufacture having a plurality ofoperating states, wherein at least one operating state of the article ofmanufacture is at least partially associated with the respectiveposition of the first connector structure and the second connectorstructure relative to each other.
 40. The apparatus of claim 27, whereinin at least the first position and the second position, at least oneelectrically conductive spring contact is electrically connected to atleast one electrically conductive contact pad.
 41. The apparatus ofclaim 27, wherein fan-out is provided by any of the first connectorstructure and the second connector structure; wherein for the firstconnector structure, the at least one contactor substrate furthercomprises an array of electrically conductive contacts on the bondingsurface, and an array of electrically conductive paths extending fromrespective electrically conductive spring contacts to correspondingelectrically conductive contacts, wherein the distance between at leasttwo electrically conductive spring contacts on the contact surface isless than the distance between any of the electrically conductivecontacts on the bonding surface; and wherein for the second connectorstructure, the array of at least one electrically conductive contact padon the first connector surface of the second connector structurecomprises a plurality of electrically conductive contact pads, whereinthe second connector structure further comprises an array of electricalcontacts on the second surface, wherein the distance between at leasttwo electrically conductive contact pads on the first connector surfaceis less than the distance between any of the electrical contacts on thesecond surface.
 42. The apparatus of claim 27, wherein the secondconnector structure further comprises an array comprising a solder balllocated on at least one of the electrically conductive contact pads onthe first connector surface.
 43. The apparatus of claim 42, wherein thespring contacts define a leading tip; wherein when the first connectorstructure and the second connector structure are in at least oneposition proximate to each other, the spring contacts are axiallypositioned with respect to the solder balls.
 44. The apparatus of claim27, wherein the second connector structure further comprises at leastone element located on the back surface of the substrate, the elementcomprising any of a second substrate, a component, a heat sink, and aconnector.
 45. The apparatus of claim 27, further comprising: at leastone structural element; wherein the bonding surface of the at least onecontactor substrate is in contact with the structural element; andwherein each of the at least one contactor substrate comprises a packageassembly.
 46. The apparatus of claim 45, wherein the structural elementcomprises any of a heat sink, a carrier, and a surface mount package.47. The apparatus of claim 27, wherein the spring contacts comprise anyof flexible springs, compliant springs, and elongate resilient probeelements.
 48. The apparatus of claim 27, wherein the contactor substratecomprises any of ceramic, multi-layer ceramic, glass ceramic, glass,quartz, glass epoxy, FR-4, polyimide, a semiconductor wafer, silicon, aprinted circuit board, one or more flip chip semiconductor devices, oneor more packaged semiconductor devices, a semiconductor integratedcircuit, and a hybrid integrated circuit.
 49. The apparatus of claim 27,wherein the substrate of the second connector structure comprises any ofceramic, multi-layer ceramic, glass ceramic, glass, quartz, glass epoxy,FR-4, polyimide, a semiconductor wafer, silicon, a printed circuitboard, one or more flip chip semiconductor devices, one or more packagedsemiconductor devices, a semiconductor integrated circuit, and a hybridintegrated circuit.
 50. The apparatus of claim 27, wherein the array ofelectrically conductive monolithically formed micro-fabricated stressmetal spring contacts is either formed on any of a sacrificial substrateand a temporary substrate and thereafter removed and affixed to thecontactor substrate; or formed in place on the contactor substrate.